<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>渐变背景</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            list-style: none;
        }
        body{
            display: flex;
            justify-content: center;
            align-items: center;
            font-size: 30px;
            height: 100vh;
            color: #fff;
            background-image: linear-gradient(
                125deg,#2c3e50,#27ae60,#2980b9,#e74c3c,#8e44ad
            );
            background-size: 400%;
            animation: bgmove 20s infinite;
        }
        @keyframes bgmove {
            0%{
                background-position: 0% 50%;
            }
            50%{
                background-position: 100% 50%;
            }
            100%{
                background-position: 0% 50%;
            }
        }
    </style>
</head>
<body>
    <h1>渐变背景</h1>
</body>
</html>